Widely deployed wireless voice and data communications systems include multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g. bandwidth and transmit power). Examples include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, GSM/GPRS systems, 3GPP Long Term Evolution (LTE) systems, and orthogonal frequency division multiple access (OFDMA) systems.
Many of these technologies currently coexist in carrier networks, requiring ongoing support of multiple Radio Access Technologies (RATs). Newer and more flexible technologies, such as LTE wireless communication networks are able to support a wide range of legacy applications, however network operators must continue to provide service to devices implementing legacy RATs.
Network operators would like to reduce the cost of overall network maintenance by minimising the number of RATs requiring ongoing deployment and support within their networks. A market experiencing ongoing expansion is that of Machine-to-Machine (M2M in ETSI terminology), or Machine-Type Communications (MTC in 3GPP terminology). MTC involves the automated communication between mechanical or electronic devices, enabling networked machines to exchange information and perform actions without the manual assistance of humans. MTC applications include smart metering, commercial fleet tracking, and so forth.
Many existing MTC devices (e.g. MTC User Equipments) are currently targeted at low-end (e.g. low average revenue per user, low data rate) applications that can be handled adequately by GSM/GPRS networks. Owing to the low cost of these MTC devices and the good coverage of GSM/GPRS, there has been very little motivation for MTC device suppliers to use modules that support the LTE radio interface. Therefore, as more MTC devices of this type are deployed in the wireless communication network, there will be an increased reliance on the existing GSM/GPRS networks. Thus, this will cost network operators not only in terms of maintaining multiple RATs but it will also prevent operators from reaping the maximum benefit out of their spectrum, especially given the non-optimal spectrum efficiency of GSM/GPRS.
According to a recent study [3GPP TR 36.888 v2.0.0 (2012-06), Study on provision of low-cost MTC UEs based on LTE, (Release 11)] the Bill Of Material (BOM) cost of an LTE User Equipment (UE) modem can be reduced to a level comparable with an EGPRS modem by reducing downlink bandwidth to, e.g., 1.4 MHz, reducing peak data rate with transport block size (TBS) restricted to 1000 bits, adopting a single receive RF chain, reducing downlink transmission modes, and adopting half duplex Frequency Division Duplex (FDD).
As the result of the study on provision of low-cost MTC UEs based on LTE, 3GPP RAN-WG1 has recommended that                peak rate reduction and bandwidth reduction be adopted as mandatory techniques,        half duplex FDD be adopted as an optional technique,        single receive RF chain be adopted only if the coverage reduction can be entirely compensated, and        an MTC-specific UE category be introduced.        